Reactor vessel having improved cup, anode, and conductor assembly

ABSTRACT

An improved anode, cup and conductor assembly for a reactor vessel includes an anode assembly supported within a cup which holds a supply of process fluid. The cup is supported around its perimeter within the reactor vessel. The anode assembly has an anode shield carrying an anode. The anode shield and the anode are supported from below by a delivery tube which also serves to deliver process fluid to the cup. A bayonet connection is provided between a top portion of the delivery tube and the anode assembly. The fluid delivery tube has a fixed height within the vessel. The anode elevation is adjusted by the interposing of a spacer of desired thickness between the anode and the tube. An electrical conductor is connected to the anode, and passes through the tube to be electrically accessible outside the vessel. The conductor is connected to the anode with a plug-in connection which is completed when the tube is coupled to the anode by the bayonet connection. The spacer is C-shaped to allow changing of the spacer for anode height adjustments without disconnecting the plug-in connection.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of Ser. No. 09/112,300,filed Jul. 9, 1998, now U.S. Pat. No. 6,288,232.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

BACKGROUND OF THE INVENTION

In the production of semiconductor integrated circuits and othersemiconductor articles from semiconductor wafers, it is often necessaryto provide multiple metal layers on the wafer to serve as interconnectmetallization which electrically connects the various devices on theintegrated circuit to one another. Traditionally, aluminum has been usedfor such interconnects, however, it is now recognized that coppermetallization may be preferable.

The semiconductor manufacturing industry has applied copper ontosemiconductor wafers by using a “damascene” electroplating process whereholes, commonly called “vias”, trenches and/or other recesses are formedonto a substrate and filled with copper. In the damascene process, thewafer is first provided with a metallic seed layer which is used toconduct electrical current during a subsequent metal electroplatingstep. The seed layer is a very thin layer of metal which can be appliedusing one or more of several processes. For example, the seed layer ofmetal can be laid down using physical vapor deposition or chemical vapordeposition processes to produce a layer on the order of 1,000 angstromsthick. The seed layer can advantageously be formed of copper, gold,nickel, palladium, or other metals. The seed layer is formed over asurface which is convoluted by the presence of the vias, trenches, orother recessed device features.

A copper layer is then electroplated onto the seed layer in the form ofa blanket layer. The blanket layer is plated to an extent which forms anoverlying layer, with the goal of providing a copper layer that fillsthe trenches and vias and extends a certain amount above these features.Such a blanket layer will typically be formed in thicknesses on theorder of 10,000 to 15,000 angstroms (1-1.5 microns).

After the blanket layer has been electroplated onto the semiconductorwafer, excess metal material present outside of the vias, trenches, orother recesses is removed. The metal is removed to provide a resultingpattern of metal layer in the semiconductor integrated circuit beingformed. The excess plated material can be removed, for example, usingchemical mechanical planarization. Chemical mechanical planarization isa processing step which uses the combined action of a chemical removalagent and an abrasive which grinds and polishes the exposed metalsurface to remove undesired parts of the metal layer applied in theelectroplating step.

The electroplating of the semiconductor wafers takes place in a reactorassembly. In such an assembly an anode electrode is disposed in aplating bath, and the wafer with the seed layer thereon is used as acathode. Only a lower face of the wafer contacts the surface of theplating bath. The wafer is held by a support system that also conductsthe requisite cathode current to the wafer. The support system maycomprise conductive fingers that secure the wafer in place and alsocontact the wafer in order to conduct electrical current for the platingoperation.

One embodiment of a reactor assembly is disclosed in U.S. Ser. No.08/988,333 filed Sep. 30, 1997 entitled “Semiconductor Plating SystemWorkpiece Support Having Workpiece—Engaging Electrodes With DistalContact Part and Dielectric Cover.” FIG. 1 illustrates such an assembly.As illustrated the assembly 10 includes reactor vessel 11 forelectroplating a metal, a processing head 12 and an electroplating bowlassembly 14.

As shown in FIG. 1, the electroplating bowl assembly 14 includes a cupassembly 16 which is disposed within a reservoir chamber 18. Cupassembly 16 includes a fluid cup 20 holding the processing fluid for theelectroplating process. The cup assembly of the illustrated embodimentalso has a depending skirt 26 which extends below a cup bottom 30 andmay have flutes open therethrough for fluid communication and release ofany gas that might collect as the reservoir chamber fills with liquid.The cup can be made from polypropylene or other suitable material.

A bottom opening in the bottom wall 30 of the cup assembly 16 receives apolypropylene riser tube 34 which is adjustable in height relativethereto by a threaded connection between the bottom wall 30 and the tube34. A fluid delivery tube 44 is disposed within the riser tube 34. Afirst end of the delivery tube 44 is secured by a threaded connection 45to an anode 42. An anode shield 40 is attached to the anode 42 by screws74. The delivery tube 44 supports the anode within the cup. The fluiddelivery tube 44 is secured to the riser tube 34 by a fitting 50. Thefitting 50 can accommodate height adjustment of the delivery tube 44within the riser tube. As such, the connection between the fitting 50and the riser tube 34 facilitates vertical adjustment of the deliverytube and thus the anode vertical position. The delivery tube 44 can bemade from a conductive material, such as titanium, and is used toconduct electrical current to the anode 42 as well as to supply fluid tothe cup.

Process fluid is provided to the cup through the delivery tube 44 andproceeds therefrom through fluid outlet openings 56. Plating fluid fillsthe cup through the openings 56, supplied from a plating fluid pump (notshown).

An upper edge of the cup side wall 60 forms a weir which limits thelevel of electroplating solution or process fluid within the cup. Thislevel is chosen so that only the bottom surface of the wafer W iscontacted by the electroplating solution. Excess solution pours overthis top edge into the reservoir chamber 18. The level of fluid in thechamber 18 can be maintained within a desired range for stability ofoperation by monitoring and controlling the fluid level with sensors andactuators. One configuration includes sensing a high level conditionusing an appropriate switch 63 and then draining fluid through a drainline controlled by a control valve (not shown). The out flow liquid fromchamber 18 can be returned to a suitable reservoir. The liquid can thenbe treated with additional plating chemicals or other constituents ofthe plating or other process liquid, and used again.

A diffusion plate 66 is provided above the anode 42 for providing a morecontrolled distribution of the fluid plating bath across the surface ofwafer W. Fluid passages in the form of perforations are provided overall, or a portion of, the diffusion plate 66 to allow fluidcommunication therethrough. The height of the diffusion plate within thecup assembly is adjustable using threaded diffusion plate heightadjustment mechanisms 70.

The anode shield 40 is secured to the underside of the consumable anode42 using anode shield fasteners 74. The anode shield prevents directimpingement on the anode by the plating solution as the solution passesinto the processing chamber. The anode shield 40 and anode shieldfasteners 74 can be made from a dielectric material, such aspolyvinylidene fluoride or polypropylene. The anode shield serves toelectrically isolate and physically protect the backside or the anode.It also reduces the consumption of organic plating liquid additives.

The processing head 12 holds a wafer W for rotation about a verticalaxis R within the processing chamber. The processing head 12 includes arotor assembly having a plurality of wafer-engaging fingers 89 that holdthe wafer against holding features of the rotor. Fingers 89 arepreferably adapted to conduct current between the wafer and a platingelectrical power supply and act as current thieves. Portions of theprocessing head 12 mate with the processing bowl assembly 14 to providea substantially closed processing volume 13.

The processing head 12 can be supported by a head operator. The headoperator can include an upper portion which is adjustable in elevationto allow height adjustment of the processing head. The head operatoralso can have a head connection shaft which is operable to pivot thehead 12 about a horizontal pivot axis. Pivotal action of the processinghead using the operator allows the processing head to be placed in anopen or faced-up position (not shown) for loading and unloading wafer W.

Processing exhaust gas must be removed from the volume 13. FIGS. 1 and 2illustrate an outer vessel side wall 76 that extends upwardly from thevessel base plate 75 to a top end into which is nested an intermediateexhaust ring 77 having circumferentially spaced- apart slots 78therethrough. The slots 78 communicate exhaust gas from inside thevessel 13 to a thin annular plenum 79 located between the intermediateexhaust ring 77 and the outer bowl side wall 76. Surrounding the outerbowl side wall 76 is a vessel ring assembly 80 which forms with the sidewall 76 an external, annular collection chamber 81. Gas which iscollected in the plenum 79 passes through intermittent orifices 82 andinto the annular collection chamber 81. Gas collected in the collectionchamber 81 is passed through an exhaust nozzle 83 to be collected andrecycled.

The above described apparatus can suffer from some drawbacks. Thethreaded connection 45 of the anode and the delivery tube may introducesome risk of thread damage during maintenance or installation of a newanode onto the delivery tube. This type of construction also makes therotational engagement and installation of, or the disengagement andremoval of, the anode to/from the delivery tube difficult and timeconsuming, due to the heavy weight of the anode and the tight clearancesbetween the anode 42 and the cup sidewall 60. The threaded connectionrequires a sufficient number of anode rotations for a complete threadedengagement during assembly, or complete threaded disengagement duringdisassembly.

Additionally, in electroplating processes using a consumable anode, itis desired to have an anodic film deposited on a surface of the anode.This film is applied to the anode before wafer processing. However, thisanodic film is very fragile and any hand or tool contact with the anodicfilm during engagement or disengagement is likely to damage the film,which must then be re-grown. This makes the threaded, rotationalmanipulation and handling of the anode during installation or removalparticularly difficult. Also, handling the anode assembly or thediffusion plate during the assembly and disassembly can contaminatesurfaces of the anode assembly, the diffusion plate, or other insidesurfaces within the volume 13.

The threaded height adjustment of the diffusion plate using threadedheight adjustment mechanisms 70 also requires a time consuming operationto precisely install the diffusion plate to the anode. A plurality ofsecurements, such as Allen head screws, are required to be removed todisassemble the diffusion plate from the anode and reinstalled duringreassembly. This is an important consideration since the diffusion platemust be removed routinely to inspect anodic film formation on the anode.The adjustment of the plural screw mechanisms can also introduce heightand level inaccuracies of the diffusion plate with respect to the anodeand/or reactor cup.

Also, the cup assembly located inside the reactor vessel is supported byan adjustable threaded engagement with the riser tube. The threadedengagement may introduce cup height and level misadjustments.

The threaded height adjustment of the anode assembly within the cup, byadjusting the delivery tube, can introduce height and levelnessmisadjustments. Additionally, the delivery tube being verticallyadjustable by loosening of a locking nut located below the reactorvessel, requires access to both the top side of the cup for viewing theanode height adjustment, and the bottom side of the vessel to loosenthis locking nut. If the reactor vessel is supported on a deck thisrequires access to both above and below the deck. Additionally, thedelivery tube being vertically adjustable at the reactor vessel baseplate requires a more complex seal mechanism between the delivery tubeand the anode post at the vessel base plate. Also, the delivery tubeserving the dual function of being a liquid conduit and an electricalconductor requires the tube to be constructed of a metallic materialwhich is conductive yet substantially inert to the process chemistry.Such a conduit has been composed of titanium, which is costly.

The present inventors have recognized that it would be advantageous toprovide a reactor vessel having an improved connection arrangementbetween anode and diffusion plate, and between anode and anode supportstructure to avoid some of the foregoing problems. Further, theinventors have recognized that it would be advantageous to provide areactor vessel arrangement that facilitates easier assembly anddisassembly of diffusion plate, anode, anode support structure and anodeelectrical conductor than found in the foregoing system. Still further,the present inventors have recognized that it would be advantageous toprovide a reactor vessel which eliminates threaded connections to asgreat a degree as possible.

The inventors have recognized that it would be advantageous to provide areactor vessel having: an improved mechanical connection arrangementbetween anode and delivery tube, an improved electrical connectionbetween anode and an outside electrical power source, an improvedaccessibility for adjusting elements of the reactor vessel, an improvedaccuracy of vertical adjustment between the anode and the cup, and animproved accuracy of vertical and level adjustment of the cup within thereactor vessel.

BRIEF SUMMARY OF THE INVENTION

An improved reactor vessel is disclosed herein. The improved reactorvessel includes a reservoir container having a base with a surroundingcontainer sidewall upstanding from the base. A cup is arranged above thebase, the cup having a bottom wall and a surrounding cup sidewallupstanding from the bottom wall, the cup sidewall defining a level ofprocess fluid held within the cup. The cup is supported within thereactor vessel on the surrounding container sidewall substantiallyaround a perimeter of the cup. Unlike the reactor vessel of FIG. 1,which supports the cup at a central location by threaded engagement withthe riser tube, the cup of the present invention is supported around itsoutside perimeter at a precise and stable level with respect to thereactor vessel. An electrode plate, such as a consumable anode, isarranged within the cup below the fluid level.

The reactor vessel includes bayonet style connections between an anodeassembly and a diffusion plate, and a bayonet style connection betweenan anode support structure and the anode assembly. A tool is providedwhich simplifies the installation and removal of the diffusion plate andthe anode assembly, while minimizing the risk of contamination or damageto the anode assembly, diffusion plate, or other surfaces within thereactor vessel.

In one embodiment, the reactor vessel includes as separate pieces, ananode electrical conductor and a fluid delivery tube. The delivery tubefunctions as the anode support structure for adjustably supporting theanode assembly, and as a conduit for delivering process fluid into thecup surrounding the anode. A corrugated sleeve or tube seals theelectrical conductor within the delivery tube.

The fluid delivery tube is fixed at its top end to the anode assembly bya bayonet connection. A protruding tip of the conductor which extendsabove the delivery tube engages a socket formed in the anode. Theengagement of the tip into the socket occurs simultaneously with theengagement of the bayonet connection. A spring within the bellows sealresiliently holds the bayonet connection in its engaged condition andassists in maintaining a sealed connection between the bellows seal andthe anode.

The delivery tube is sealed to the base and extends through the cupbottom wall to support the anode assembly from the base. The tube has asubstantially closed bottom and a top. The anode electrical conductorincludes a conductor wire which is arranged within the tube and passestrough the tube bottom and top, the conductor wire being connected tothe protruding tip. The tube includes an inlet opening for receivingprocess fluid, and at least one outlet opening into the cup.

The reactor vessel includes a fixed incremental vertical adjustment andlevel adjustment between the anode assembly and the reactor cup. Aspacer (or spacers) having a desired thickness is (are) interposedbetween the anode and the delivery tube to set the anode height withinthe cup. The spacer is C-shaped so as to be installable without completedismantling of the electrical conductor assembly. The electricalconductor includes an excess length within the delivery tube for thepurpose of allowing room for the removal and installation of theC-shaped spacer during level adjustment of the cup.

The anode assembly includes an anode shield that carries the anode. Aplurality of brackets, preferably formed as a unitary structure with theanode shield, extend upwardly from the anode. The diffusion plate isconnected to the plurality of brackets by a bayonet connection at eachbracket The diffusion plate is thus held elevated above the anode.

The reactor vessel configuration simplifies construction and assemblythereof. The anode assembly can easily be removed from the fluiddelivery tube and the electrical conductor disconnected from the anodedue to the bayonet connection between the delivery tube and the anode,and the tip/socket connection between the electrical conductor and theanode. A threaded connection between anode assembly and delivery tube iseliminated. Misadjustment of the anode assembly caused by the threadedconnection between delivery tube and the anode assembly is eliminated.Assembly drawbacks associated with threaded connections such as damagedthreads, and time consuming assembly/disassembly are reduced or avoided.The anode assembly need only be depressed, turned and withdrawn to bedisengaged and removed from the reactor vessel.

The level adjustment of the anode can be accomplished entirely withaccess only on a top side of the reactor. No loosening operation orthreaded adjustment on a bottom side of the reactor is required. Theanode can be removed and installed from a top side of the reactor. Theprotruding tip and its associated flange can then be lifted up so thatthe spacer can be exchanged with a replacement spacer or spacers, for amore precise height or level adjustment.

By replacing the delivery tube having a threaded vertical adjustment atthe vessel bottom wall with a fixed delivery tube having no relativemovement between the vessel bottom wall and the tube, a reduced sealmechanism complexity is achieved for the delivery tube at the vesselbottom wall. The delivery tube can be permanently sealed to the vesselbottom wall without provision for relative vertical adjustment betweenthe delivery tube and an anode post at the bottom wall.

A conductor wire sealed from the process fluid by a dielectric sleeve isused in combination with a dielectric material delivery tube resultingin an effective and more cost efficient construction. By separating theprocess fluid delivery function from the electrical conduction function,the need for a costly titanium delivery tube is eliminated.

The diffusion plate is more easily removed and reinstalled by virtue ofthe bayonet connections at each of the brackets of the anode shield. Thesmall screws which were previously required to be removed with, forexample, an Allen wrench, to remove the diffusion plate from thediffusion plate height adjusting mechanism, are eliminated.Additionally, the threaded height adjustment mechanisms are eliminatedwhich could otherwise adversely vary the installed height or levelnessof the diffusion plate.

A multi-function tool is also provided which functions to engage andinstall/remove the diffusion plate from the anode assembly, and also toengage and install/remove the anode assembly from the fluid deliverytube. The tool reduces or eliminates handling of the diffusion plate andthe anode assembly during installation or removal which can cause anodicfilm damage, contamination and damage to the diffusion plate or anodeassembly or the vessel interior.

An additional advantage of the bayonet connections of the diffusionplate and the anode in combination with the multi-function tool is thefact that a reduced overhead clearance is required to remove thediffusion plate and the anode. In comparison, to manually detach andremove, and later reinstall, the diffusion plate and anode of thereactor shown in FIG. 1, the entire head assembly including the lift androtate mechanism which manipulates the rotor must be removed. After thereactor is reassembled and the head assembly is reinstalled, the waferloading robot or manipulator (not shown) which loads wafers onto therotor, must be reinstructed or recalibrated to ensure an accurateplacement of wafers on the rotor. This step is time consuming andcostly. Because the diffusion plate and anode assembly of the presentinvention can be manipulated and removed using simplified handmanipulations with the multi-function tool, it is possible that the liftand rotate mechanism can remain in place and only the rotor removed fromthe processing head to obtain enough access for diffusion plate andanode assembly removal and reinstallation. It is anticipated that thisadvantage of the invention will result in a reduced disassembly,inspection, and reassembly time during maintenance of the reactorvessel.

Numerous other advantages and features of the present invention willbecome readily apparent from the following detailed description of theinvention and the embodiments thereof, from the claims and from theaccompanying drawings in which details of the invention are fully andcompletely disclosed as part of this specification.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an exploded partially sectional view of a reactor vessel andprocessing head;

FIG. 2 is an enlarged fragmentary sectional view taken from FIG. 1;

FIG. 3 is a perspective view of a reactor vessel constructed inaccordance with one embodiment of the present invention;

FIG. 4 is an exploded perspective view of the reactor vessel of FIG. 3;

FIG. 5 is a top view of the reactor vessel of FIG. 3;

FIG. 6 is a bottom view of the reactor vessel of FIG. 3;

FIG. 7 is a sectional view taken generally along line 7—7 of FIG. 5;

FIG. 7A is an enlarged fragmentary sectional view from FIG. 7;

FIG. 8 is a sectional view taken generally along line 8—8 of FIG. 5;

FIG. 9 is a sectional view taken generally along 9—9 of FIG. 5;

FIG. 10 is an enlarged perspective view of a fluid delivery tube shownin FIG. 7;

FIG. 11 is an exploded perspective view of one embodiment of an anodeconductor assembly;

FIG. 12 is a sectional view of the anode conductor assembly of FIG. 11;

FIG. 13 is an enlarged fragmentary sectional view of the anode conductorassembly of FIG. 12;

FIG. 14 is a top perspective view of a diffusion plate and anoderemoval/installation tool constructed in accordance with one embodimentof the present invention;

FIG. 15 is a bottom perspective view of the tool of FIG. 14;

FIG. 16 is a fragmentary bottom perspective view of an alternate lockpin arrangement for the tool in FIG. 14;

FIG. 17 is a perspective view of one embodiment of an anode shield asused in the reactor vessel of FIG. 3;

FIG. 18 is a fragmentary, enlarged perspective view of the anode shieldof FIG. 17;

FIG. 19 is an exploded perspective view of one embodiment of a diffusionplate as used in the reactor vessel of FIG. 3;

FIG. 20 is a perspective view of the diffusion plate of FIG. 19; and

FIG. 21 is a bottom perspective view of one embodiment of a bottom ringportion of the diffusion plate of FIG. 19.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiment in many differentforms, there are shown in the drawings and will be described herein indetail specific embodiments thereof with the understanding that thepresent disclosure is to be considered as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the specific embodiments illustrated.

FIGS. 3-6 illustrate a reactor vessel 100 which is to be used incooperation with a processing head 12 (as shown in FIG. 1). Theprocessing head 12 may, for example, be of the type disclosed in U.S.Ser. No. 08/988,333 filed Sep. 30, 1997, now U.S. Pat. No. 5,985,126,entitled: “Semiconductor Plating System Workpiece Support HavingWorkpiece—Engaging Electrodes With Distal Contact Part and DielectricCover” herein incorporated by reference. The processing head holds awafer to be processed within a substantially closed processing volume103 of the reactor vessel 100, and rotates the wafer during processing.The vessel 100 is shown without a vessel exhaust ring assembly forclarity to illustrate the underlying parts. It is to be understood thatthe outer vessel exhaust ring assembly 80 and exhaust nozzle 83 as shownfor example in FIG. 1 would be mounted around the vessel 100 as shownfor example in FIG. 2.

The reactor vessel 100 includes a rotor supporting ring or rim 110mounted on an inner exhaust ring 124 which is carried on a reservoircontainer 120. A diffusion plate 112 is carried by an anode shield 116which, in turn, carries an anode 114. The anode 114 is preferably aconsumable anode composed of copper or other plating material. The anode114 and the anode shield 116 are fastened together forming an anodeassembly 117. A reactor cup assembly 118 is supported on, and partiallyheld within, a reservoir container assembly 120. An anode electricalconductor assembly 122 extends vertically through the reservoircontainer 120 and makes electrical connection with the anode 114 asdescribed below. A de-plating electrode 123 in the form of a ring 123 aand a contact support 123 b allows for periodic de-plating ofwafer-engaging fingers 89 (shown in FIG. 1).

FIGS. 7-9 illustrate the rotor support ring 110 nesting into the exhaustring 124 of the reservoir container assembly 120. The cup assembly 118includes a cup inner sidewall 130 defining at its upper edge 130 a anoverflow weir, and a cup outer sidewall 131 which extends upward to abottom 110 a of the rotor support ring 110. The inner and outersidewalls 130, 131 are radially connected by intermittent webs 132formed integrally with the sidewalls 130, 131. A container or “cup” 139for holding process fluid is formed by a cup bottom wall 138 and theinner sidewall 130.

The reservoir container assembly 120 includes a surrounding reservoirsidewall 140 that is sealed to a base plate 142 and supports the exhaustring 124 at a top thereof The cup assembly 118 is supported by an outeredge 131 b of the outer sidewall 131 resting on a ledge 124 a of theexhaust ring 124 which, in turn, is supported by a top edge 140 a of thevessel sidewall 140. Thus the elevation and level of the cup assembly118 is preferably fixed, i.e., it is non-adjustable with respect to thereservoir 120.

The anode 114 is connected by fasteners (as shown for example in FIG. 1)to the anode shield 116. The anode 114 is supported within the cupsidewall 130 by an anode support structure such as a fluid delivery tubeor “anode post” 134. The anode post 134 is in the form of a cylindricaltube (see FIG. 10) having top and bottom ends substantially closed asdescribed below. The anode post 134 extends through an opening 143through the reservoir base plate 142 and through an opening 136 in thecup bottom wall 138. The anode post 134 is sealed to the cup bottom wall138 around the opening 136 with an O-ring 137. Further, the anode postis sealed to the base plate 142 around the opening 143 by plasticwelding or other sealing technique.

Extending downwardly from the cup sidewall 130 is a fluted skirt 148having a plurality of slots 150 for allowing passage of process fluids.Through the base plate 142 of the reservoir container 120 passes anoverflow standpipe 154 having an open end 155 for receiving processfluid. Also, connected to the bottom wall 142 is a process outlet 158for the draining of process fluid from the reservoir container 120. Itis to be understood that the standpipe 154 and the process outlet 158would be connected to process piping to deliver process fluid to arecycling system or other process fluid system. In this regard, aprecise control of the process fluid level in the container 120 can bemaintained through use of a high process fluid level switch 170 and alow process fluid level switch 171 within the container 120 which openand close a control valve (not shown) connected to the outlet 158.

The anode electrical conductor assembly 122 includes at a bottom endthereof, a fitting 190 having a bottom region 191 threaded for receivinga nut 192. The fitting 190 can be firmly tightened to a bottom wall 200of the anode post 134. The fitting 190 includes a top flange 190 a withan O-ring seal element 190 b which is drawn into sealing engagement withthe top surface 200 a of the wall 200 by advancement of the nut 192 onthe fitting 190.

The anode post 134 includes an internal volume 204 in fluidcommunication with outlet openings 206 (shown in FIG. 8), and with abottom supply nozzle 208 (shown in FIG. 8), for delivering process fluidinto the cup 139, from an outside source of process fluid. The anodepost 134 is closed at a top end by a top cap 194.

The anode electrical conductor assembly 122 includes a corrugated sleeve210 sealed by a first coupling 212 to a neck 213 of the fitting 190. Thesleeve surrounds a conductor wire 221 shown schematically as a line. Thewire 221 is not shown in FIGS. 8 and 9 for clarity. The corrugatedsleeve 210 extends upwardly and is sealed to a neck 225 of a fitting 195of the top cap 194 by a second coupling 224.

FIG. 7A illustrates the sealing arrangement used at the couplings 212,224. The necks 213, 225 receive a pre-flared, non-corrugated end 210 b(or 210 c) of the corrugated sleeve 210 which is then compressed by atapered inside surface 225 a of the respective coupling 212, 224,against a tapered outer surface 225 b of the respective necks as thecoupling threads 226 are advanced on respective fitting threads 227.This sealing arrangement is similar to commercially available flaredfittings.

The top cap 194 includes a support ring 240. The support ring guides aconductor tip 220 held vertically within a central aperture of thesupport ring. The tip 220 is electrically connected to the conductorwire 221. The cap 194 further includes a surrounding guide ring 242around which is carried a bellows seal 260 which extends upwardly fromthe cap 194. The bellows seal surrounds the tip 220 and, in its relaxedstate, extends to a position upwardly thereof. The bellows seal 260includes a top opening 262 in registry with the tip 220, and asurrounding groove 260 c for holding an O-ring seal element 260 b (seeFIGS. 11-13).

The top cap 194 is substantially cross-shaped in plan view, having aplurality of fastener holes 194 a (see FIG. 11). A substantiallycircular, dished attachment plate 264 is arranged coaxially with the topcap 194 and includes a central aperture 266 for receiving the guide ring242 of the top cap 194. The attachment plate 264, and the cap 194 arefastened together and to the post 134, via an interposed spacer 228, byfour fasteners 229. The fasteners are fit into four holes 264a throughthe attachment plate 264 (shown in FIG. 4), the four fastener holes 194athrough the top cap 194, four holes 228 a through the spacer (shown inFIG. 4), and then threaded into four threaded holes 134 a of the anodepost (shown in FIG. 10). The spacer 228 is selected for a precisethickness to set the elevation of the anode 114 with respect to the cupassembly 118, particularly with respect to the top edge 130 a of thesidewall 130.

The attachment plate 264 is connected to the anode assembly by a bayonetconnection. A bayonet connection is characterized as one in which onepart is connected to another part by first a movement toward each otherand then a second relative rotational movement between the parts. Theattachment plate 264 includes a plurality of spaced apart, radiallyextending tabs 265. During installation of the anode assembly, the tabs265 vertically enter vertical slots 267 (see FIGS. 9, 17 and 18) formedin the anode shield 116, and upon turning of the anode assembly 117 fromabove, the tabs 265 are advanced relatively in circular, substantiallyhorizontal slots 268 formed between the anode 114 and the shield 116.The horizontal slots 268 each terminate in a tab-receiving recess 269which restrains the tabs from rotational disengagement once completelyinstalled. Spring force from a bellows spring (described below) holdsthe tabs 265 within the recesses 269. During engagement of the tabs 265,the bellows 260 and bellows spring are vertically compressed as the tip220 is plugged into a socket 270 formed in the anode 114 to make a solid“plug-in” or “plug-and-socket” electrical connection thereto.

To disengage the anode assembly from the attachment plate 264, the anodeis pressed downwardly to elevate and disengage the tabs 265 from therecesses 269, and the anode is turned or rotated to align the tabs withthe vertical slots 267. The anode assembly can then be withdrawnupwardly. The tip 220 will be pulled free from the socket 270 andresiliently open up once free of the socket.

It can be observed that the height adjustment of the anode can be setentirely from above. First, the anode 114 and shield 116 are removedfrom the attachment plate 264. Second, the attachment plate is removedfrom the post 134 by removal of the fasteners 229. Third, the cap 194 islifted upwardly, and the spacer 228 is replaced with a spacer having adesired thickness dimension. As shown in FIG. 4 the spacer 228 isC-shaped to facilitate replacement around the conductor assembly 122without complete disassembly thereof, i.e., there is no need to removethe tip 220 or the top cap 194 from the conductor wire.

As illustrated particularly in FIGS. 8 and 9, the diffusion plate 112 isconnected to intermittently arranged upstanding bracket members 274using bayonet connections. As shown in FIGS. 9 and 21, a connector ring278 of the diffusion plate 112 has a C-shaped cross-section forming achannel 279. Each bracket 274 includes a vertical leg 275 and aradially, outwardly extending tab member 280. During installation, eachtab member 280 enters a wide slot or recess 281 through the bottom leg279 a of the C-shaped cross-section. Upon relative turning between thering 278 and the bracket 274, each vertical leg 275 of each bracket 274resiliently passes a detent 282 and enters a more narrow slot or recess283. Each detent 282 thus resiliently locks a bracket member 274 to theconnector ring 278. To remove the diffusion plate 112 from the anodeassembly 117, the plate is rotated in an opposite direction. The legs275 resiliently deflect radially inwardly a sufficient amount to passthe detents 282. Finally, the tab members 280 are withdrawn through therecesses 281.

FIGS. 11-13 illustrate the construction of one embodiment of the anodeconductor assembly in more detail. As illustrated, the anode tip 220 hasa profile which compresses when installed in the socket 270 of theanode. The tip includes a small diameter distal end region 220 a, a widecentral region 220 b, and a narrow base region 220 c. The base region220 c terminates at a flange or stop 220 d which sets the extension ofthe tip 220 from the support ring 240 of the cap 194.

The tip 220 includes a soldering connection or crimping region 220 e ata bottom end thereof that is used for connecting it to the conductorwire 221 (shown schematically in FIG. 12). The conductor wire 221extends downwardly from the tip 220 through the fitting 195 of the cap194, the corrugated sleeve 210, and the bottom fitting 190. From thebottom fitting 190, the wire 221 extends externally of the reactorvessel 100 for connection to a plating power supply.

The corrugated sleeve 210 includes a corrugated length 210 a between thecouplings 212, 224 and a first non-corrugated portion 210 b whichover-fits the neck 225 of the fitting 195, and a second non-corrugatedportion 210 c which over-fits the neck 213 of the fitting 190 asillustrated in FIG. 7A. The couplings 212, 224, by progressive threadedtightening onto the respective necks 213, 225, seal the non-corrugatedregions 210 b, 210 c onto the fittings 190, 195 to form a sealedconfiguration around the conductor wire within the anode post 134.

FIG. 11 illustrates the assembly of the conductor assembly 122, absentthe wire conductor for clarity. The O-ring 260 b is arranged to fitwithin a channel 260 c of the bellows 260. Another O-ring 242 a isarranged to fit within a channel 242 b (see FIG. 13) of the guide ring242 to seal the bellows 260 to the top cap 194.

As illustrated in FIG. 13, a bellows coil spring 290 is fit within thebellows 260 and the top cap 194. The spring 290 is fit within an annularchannel 292 formed between the guide ring 242 and the support ring 240.The spring 290 urges the anode assembly away from the attachment plate264 to resiliently seat the tabs 265 in the tab-receiving recesses 269.Additionally, the spring acts to press the O-ring 260 b into the anodeto effect a tight seal thereto.

FIG. 14 illustrates a multi-function diffusion plate and anoderemoval/installation tool 300 of the present invention. The tool 300includes a disc structure 302 having a central hole 304. Bridging acrossthe central hole is a handle 306. The handle is held to the discstructure by fasteners 307 (shown in FIG. 15). A lock pin 308 having agrip head 310 penetrates a pin receiving hole 312 through the discstructure 302.

As illustrated in FIG. 15, the disc structure includes four L-shapedhook arms 320, each having a vertical leg 322 and a radially inwardlydirected detent or hook portion 324. In operation, the hook arms 320extend downwardly. The hook arms 320 are configured and arranged toengage bayonet recesses 330 formed through an outside of a topperforated plate 112 a of the diffusion plate 112 as illustrated inFIGS. 5, 19 and 20. Each recess 330 includes a wide region 332 forreceiving a hook portion 324, and two narrow regions 334 for snuglyreceiving a leg 322 into a locked position (in either directiondepending on whether removal or installation is taking place). When theleg 322 moves in this position, the hook portion 324 is located belowthe top perforated plate 112 a. The tool with engaged diffusion platecan then be rotated in one direction to remove the diffusion plate 112,or rotate in an opposite direction to install the diffusion plate 112from or onto the brackets 274.

The tool 300 also serves as an anode assembly removal/installation toolonce the diffusion plate 112 has been removed. On a bottom surface ofthe tool 300 are located four bracket/engaging recesses 340 that arespaced apart to mate with the brackets 274 of the anode shield 116. Eachrecess 340 includes a recess region 342 for receiving the radiallyturned end of the bracket 274 therethrough. A further recess region 344is defined at least in part, by a radially extending ledge 346.Extending vertically from the disc structure 302 are four guide pins348. Each guide pin 348 is radially spaced from a respective ledge 346by a distance approximately equal to, or greater than, a radialthickness of a respective bracket vertical leg 275. Thus, in operation,the tool 300 is placed onto the anode assembly 117 with each bracket 274received into one of the wide recess regions 342. The tab member 280 ofeach bracket 274 is located above a respective ledge 346. The tool isthen rotated relative to the anode such that the vertical leg 275 ofeach bracket 274 slides circumferentially between a respective ledge 346and a respective guide pin 348. The tab member 280 of each bracket 274is thus captured above the respective ledge 346.

The lock pin 308 is operated by force of gravity to fall to a positionbehind one of the brackets 274 which has passed into the narrow recessregion 344. The lock pin 308 thus prevents inadvertent reverse rotationof the tool relative to the anode. This prevents accidental separationof the tool and the relatively heavy anode assembly during removal,assembly or transporting of the anode assembly. The lock pin 308 ispreferably formed of two pieces: a bottom piece 308 a, having a toolengageable head 350 connected to a first barrel 352, and a top piece 308b which includes the gripping head 310 connected to a second barrel 354.The first barrel has a male threaded extension (not shown) which isengaged by a female threaded socket (not shown) of the second barrel.Thus relative rotation of the first and second barrels can separate orjoin the two pieces 308 a, 308 b at a seam 308 c for disassembly orassembly of the pin 308. The gripping head 310 and the engageable head350 allow retention of the pin to the interposed disc structure 302,while still allowing vertical reciprocation with respect thereto.

Additionally, as illustrated in FIG. 16, the lock pin can alternately beconfigured to allow lifting of the lock pin by sliding pressure (ratherthan manual lifting) of the respective bracket 274 during engagement ofthe tool to the anode assembly. The pin is designed to be lifted by thetop surface of the tab 274 as it enters the slot 342 and then falls intoposition upon rotation of the handle. The lock pin however can requiremanual lifting of the pin to disengage the tool from the anode assembly,by relative rotation therebetween. This is accomplished, for example, bya ratchet tooth shaped pin 350, wherein the ratchet tooth shaped pinwould provide a slanted surface 352 facing an engagement direction withthe bracket 274. The pin 350 includes a vertical surface 354 facing atool disengagement direction. A retaining mechanism such as a detent(not shown) or a two piece construction with enlarged heads (such asdescribed with regard to the pin 308) can be provided on the shaped pinto prevent separating of the shaped pin from the interposed discstructure 302. The retaining mechanism would allow verticalreciprocation of the pin with respect to the disc structure.

The tool 300 thus provides an effective means to disassemble andreassemble the diffusion plate and anode assembly from the vessel. Thetool also reduces contact, damage and contamination of the anode andanode film.

FIGS. 19-20 illustrate the diffusion plate 112 in detail. The diffusionplate includes the top perforated plate 112 a which is attached byfasteners (not shown) through four fastener hole pairs 297 a, 297 b tothe connector ring 278, capturing a spacer ring 298 therebetween. Theholes 297 b are threaded to engage the fasteners. The spacer ring 298has a smaller outside diameter D1 than an inside diameter D2 betweendiametrically opposing wide recesses 332 to ensure noninterference ofthe spacer ring 298 with the hook arms 320 of the tool 300 duringinstallation or removal of the diffusion plate. The thickness of thespacer ring 298 provides a vertical space below the perforated plate 112a, particularly below the bayonet recesses 330, for the hook portion 324to be received.

In the disclosed embodiment, the cup assembly 118, the anode post 134,the reservoir container 120, the anode shield 116, the diffusion plate112, the exhaust ring 124, the rotor support ring 110, the corrugatedsleeve 210, the spacer 228, the fasteners 229, the top cap 194, thefitting 190, the nut 192, the couplings 212, 224, and the attachmentplate 264, are all preferably composed of dielectric materials such asnatural polypropylene or polyvinylidene fluoride. The conductor wire 221is preferably composed of copper or another appropriate conductor, as isthe tip which also can be gold plated for enhanced electrical contact.The bellows seal 260 is preferably composed of a Teflon material. Thebellows spring is preferably composed of stainless steel. The variousO-rings are preferably composed of an acid compatible fluoro-elastomer,depending on the process fluid.

Numerous modifications may be made to the foregoing system withoutdeparting from the basic teachings thereof. Although the presentinvention has been described in substantial detail with reference to oneor more specific embodiments, those of skill in the art will recognizethat changes may be made thereto without departing from the scope andspirit of the invention as set forth in the appended claims.

What is claimed is:
 1. A reactor vessel for electroplating amicroelectronic workpiece, comprising: a reservoir container including abase plate and a surrounding container side wall upstanding from saidbase plate; a cup arranged above said base plate, said cup having abottom wall and a surrounding cup side wall upstanding from said bottomwall, said cup sidewall defining a level for a process fluid within saidcup during operation; an anode arranged within said cup below saidlevel; and an anode support arranged beneath said anode and supportedfrom said base plate, the anode being removably attached to the anodesupport, the anode support having a first portion, a second portionremovably attached to the anode, and a spacer removably positionedbetween the first and second portions, the spacer having a thicknessselected to position the anode at one of a plurality of selectabledistances from said level defined by the cup sidewall.
 2. The reactorvessel according to claim 1, further comprising a conductor wirearranged within said anode support and having a plug electricallyconnected to said anode.
 3. The reactor vessel according to claim 2,wherein said anode support includes a tube having an inlet opening forreceiving process fluid, and at least one outlet opening into said cup,and said tube surrounding said conductor wire.
 4. The reactor vesselaccording to claim 3, further comprising a sleeve surrounding saidconductor wire and sealed to said anode and to a bottom of said tube. 5.The reactor vessel according to claim 4, including a bellows sealsurrounding said plug, and said tube mechanically connectable to saidanode, said anode having a socket for receiving said plug to makeelectrical connection thereto, said bellows seal partially compressed toseal against said anode when said plug is received into said socket. 6.The reactor vessel according to claim 1, further comprising: a structurefor supporting the cup within the reactor vessel, said structure carriedby said surrounding container sidewall, said structure supporting saidcup around a perimeter of said cup.
 7. The reactor vessel according toclaim 1, wherein said spacer is generally C-shaped.
 8. The reactorvessel according to claim 2, wherein said spacer is generally C-shaped.9. The reactor vessel according to claim 2, wherein said spacer includesa slot to allow removal and installation of the spacer withoutdisconnection of said plug from said anode.
 10. The reactor vessel ofclaim 1 wherein the anode support includes a tube portion having a flowpassage with an outlet in the cup and an inlet outside the cup, theanode support further having an anode shield portion positioned beneaththe anode, the anode being removably attached to the anode shieldportion.
 11. The reactor vessel of claim 1 wherein the spacer is thefirst of two spacers, the first spacer having a first thickness toposition the anode a first distance from said level, the second spacerhaving a second thickness to position the anode a second distance fromsaid level, the second distance being different than the first distance.